| Abstract: | Metallized, flexible polymeric reflector materials are much lighter and potentially less expensive than the conventional glass/metal mirrors often used in solar thermal concentrators such as heliostats and parabolic dishes and troughs. Unweathered silvered-PMMA reflectors have a solar reflectance at least as high as glass reflectors, but their environmental durability needs to be demonstrated. ECP-305, a silvered-PMMA film available commercially from the 3M Company and developed in collaboration with the National Renewable Energy Laboratory, is the current state of the art. Important progress has been made in overcoming the three primary mechanisms causing ECP-305 to lose reflectance. These mechanisms are: (1) photon-induced silver corrosion, (2) surface soiling, and (3) a form of delamination called tunneling. Given the progress in resolving these performance lifetime issues, silvered-PMMA films should meet the reflectance and durability goals. |
